1. Field of the Invention
This invention relates to a radiation image read out and reproducing apparatus for use in a radiation image recording and reproducing system, wherein both read-out and reproduction of a radiation image are carried out by use of the same scanning system in the same apparatus.
2. Description of the Prior Art
When certain kinds of phosphors are exposed to radiation such as X-ray, .alpha.-ray, .beta.-ray, .gamma.-rays, cathode rays or ultraviolet rays, they store part of the energy of the radiation. Then, when the phosphor which has been exposed to the radiation is exposed to stimulating rays such as visible light, light is emitted by the phosphor in proportion to the stored energy of the radiation. A phosphor exhibiting such properties is referred to as a stimulable phosphor.
As disclosed in U.S. Pat. Nos. 4,258,264, 4,276,473, 4,315,318 and 4,387,428 and Japanese Unexamined Patent Publication No. 56(1981)-11395, it has been proposed to use a stimulable phosphor in a radiation image recording and reproducing system. Specifically, a sheet provided with a layer of the stimulable phosphor (hereinafter referred to as a stimulable phosphor sheet) is first exposed to radiation passing through an object such as the human body in order to have a radiation image of the object stored thereon, and is then scanned with stimulating rays, such as a laser beam, which cause it to emit light in proportion to the stored radiation energy. The light emitted by the stimulable phosphor sheet upon stimulation thereof is photoelectrically detected and converted into an electric image signal, and from the image signal the radiation image of the object is reproduced as a visible image on a recording material such as photographic film, a display device such as a cathode ray tube (CRT), or the like.
In the aforesaid radiation image recording and reproducing system, the stimulable phosphor sheet is used to temporarily store a radiation image until the sheet is scanned with stimulating rays to read out the radiation image. Therefore, after the radiation image is read out from the stimulable phosphor sheet, radiation energy remaining thereon should be erased so that the stimulable phosphor sheet may be reused.
The aforesaid radiation image recording and reproducing system has heretofore been composed of a recording apparatus for storing a radiation image on a stimulable phosphor sheet, a radiation image read-out apparatus for reading out the radiation image stored on the stimulable phosphor sheet and generating an image signal therefrom, and an image reproducing apparatus for reproducing a visible radiation image by, for example, scanning a recording sheet with a light beam modulated in accordance with the image signal and thus recording the visible radiation image on the recording sheet. Therefore, in order to form the final visible image of the radiation image, which was stored on the stimulable phosphor sheet, on the recording sheet in the conventional radiation image recording and reproducing system, it is necessary to provide two independent apparatuses, i.e. the read-out apparatus for reading out the radiation image from the stimulable phosphor sheet and the reproducing apparatus for reproducing the radiation image on the recording sheet, besides the recording apparatus.
In recent years, various attempts have been made to make the aforesaid radiation image recording and reproducing system small in size and to reduce the manufacturing cost of the system. However, with the conventional radiation image recording and reproducing system, the read-out apparatus and the reproducing apparatus must be provided independently of each other as mentioned above, and the size of the system as a whole is not small. Also, a scanning system and other components must be provided independently in each of the read-out apparatus and the reproducing apparatus, and therefore the manufacturing cost of the radiation image recording and reproducing system cannot be kept low.
Though an X-ray image read-out and reproducing apparatus, wherein the same light source is utilized for read-out and reproduction and read-out and reproduction are carried out alternately in one stage, is proposed in Japanese Unexamined Patent Publication No. 58(1983)-184677, only a conceptual view of the apparatus is shown in the specification thereof and no concrete configuration of the apparatus is described therein. Therefore, it is not possible to put the sapparatus into practice as it is disclosed. Also, with the proposed apparatus, scanning is carried out by moving the light source and a photodetector with respect to a sheet. With such a scanning method, the movement mechanism becomes complicated and it is not always possible to achieve quick scanning. Further, the proposed apparatus is complicated because a light modulator and the photodetector are moved by a drive mechanism into and out of the optical path of the light emitted by the light source in the course of change-over of the apparatus between its read-out and reproduction modes.
Also, when the radiation image is reproduced into a visible image by the reproducing apparatus, it is often desired that the sex, name, date of image recording and information about the object be displayed together with the radiation image. Such ID information has heretofore been recorded on an ID card or the like by a special ID entry means at the time of image recording. The entered information is transmitted to the reproducing apparatus at the time of image reproduction, and displayed on the reproducing apparatus together with the radiation image. However, in this case, a special entry means is necessary, and therefore the overall radiation image recording and reproducing system becomes complicated. Also, the ID information entry operation is troublesome, and the entry and reproduction of the ID information cannot always be carried out because there is a standard format for the ID information which is to be entered and the number of characters specifying the ID information is limited.